Giant Whitefly in San Diego County

I may have missed it in San Diego County in previous years since its introduction to California in 1993 but this species is certainly here this year. I have reports from Chula Vista, San Diego, Del Mar and farther north.

Reported food plants include: Hibiscus (Chula Vista, San Diego)
Cocklebur (Torrey Pines State Reserve - Del Mar)
acacia (Sydney Whattle (sp?)) (Torrey Pines State Reserve - Del Mar)
begonia (Del Mar)
tomato and peppers

Egg spirals have also been found on: Tree Tobacco leaves (Torrey Pines State Reserve - Del Mar)
    (adults and larvae were found farther into the reserve 18 Aug 96)
Castor Bean leaves (Torrey Pines State Reserve - Del Mar)

The eggs are generally laid in a spiral pattern apparently with a lot of wax on the undersides of the leaves of the host plant. The first instar larvae, the crawlers, appear to settle close to the spiral, and the second and third instar larvae develop there. The second and third instar larvae are green to yellow-green ovals that blend well with the leaves they are feeding on. The fourth instar larvae are covered with a white wax and numerous very long waxy filaments. Leaves supporting colonies of fourth instar larva appear to be growing long flowing white beards.

spiral egg pattern on cocklebur
    3 mites can be seen above egg spiral on left side
    another mite is just above the minor vein on the right hand side
second and third instar larvae in egg spiral
fourth instar larvae showing long filaments
adults and larvae with egg spiral visible
Hibiscus leaf showing fourth instar beard (San Diego)

On the cocklebur at Torrey Pines, these insects were found in association with several kinds of flies, a couple of wasps, a number of beetles (some very small black beetles, a Mealybug Destroyer Ladybird, and a number of patterned brown beetles), a number of beetle larvae, and many small red mites. A few ants were found. Other than one lacewing egg, no potential predators were found on the acacia, Tree Tobacco or Castor Bean (the latter having egg spirals only).

In Dec 1996 the California Department of Food and Agriculture (CDFA) issued a press release on the Giant Whitefly Project in San Diego. The article was on the web for a time but the link I had to it no longer functions. The early project was set back by the El nino conditions occurring during the winter of 1997 and the spring of 1998. People interested in the current status of the project - details of the Giant Whitefly beyond those given above, plus control methods, and host plants - are encouraged to consult the Giant Whitefly Project Web Site. Other information can be obtained using the web search engines. Many online gardening columns discuss this insect.

Ron Lyons (volunteer 1990-1999)
Chula Vista Nature Center, 1000 Gunpowder Point Drive, Chula Vista, CA 91910-1201